Research: Micro-labs' potential for brewing up trouble have new significance in the wake of terrorist threats.

"These are the active cultures that I use," he says proudly, ticking off the contents of each glass vial. "Staphylococcus aureus, Enterococcus, E. coli, Bacillus cereus.

"Also, if I need it. . . . " he adds, squeezing between the bed and a chest of drawers.

Harris pulls a vial out of a dormitory-size fridge and holds it between thumb and forefinger. He peers at it though his reading glasses, his Santa Claus beard spreading over his chest like a bib.

It is anthrax, albeit a harmless form used for inoculating livestock against the disease.

"It cannot make you sick, nor can it be made to make you sick," Harris says reassuringly.

There is nothing about Harris' small wood-frame house, neatly planted in a modest suburban neighborhood of minivans and chain-link fences, to suggest the presence of live anthrax bacteria inside. Even in his bedroom laboratory, there are just a few scientific accouterments, none very sophisticated. His lab bench is an old bedroom vanity. His supply closet is an armoire. The centrifuge on the dresser might look familiar to anybody who took high school biology in the 1950s.

This tiny home lab could never produce anything like the high-grade anthrax that started turning up at news organizations and in Capitol Hill mailboxes last fall.

Even so, federal agents investigating the mail attacks have taken a keen interest in Harris and anybody remotely like him. An FBI profile in November described a loner with "access to some laboratory equipment" who "has a scientific background, or at least a strong interest in science."

That's Harris. And to a greater or lesser extent, the FBI profile describes a surprisingly robust network of people like him.

These are citizen-scientists who conduct their experiments outside of the big institutions--universities, pharmaceutical companies and government laboratories--that control biological research today. They vary greatly in academic credentials and their access to sophisticated equipment.

Some don't have college degrees; others have PhDs and experience directing university laboratories.

Some perform their experiments in basements, spare bedrooms and rented offices in suburban office parks. They use secondhand equipment, modified kitchenware, whatever they can scrounge up with their own money or donations.

A select few have their own research institutes, and in some cases they have even attracted federal funding by circumventing the process the government uses to dole out research money. But their theories and goals are dismissed, and sometimes even discredited, by the scientific establishment.

It wasn't always this way. For centuries, amateurs were the backbone of science. The founder of microbiology, Anton van Leeuwenhoek, was a Dutch fabric salesman who enjoyed making optical instruments out of glass lenses that he ground himself. One of his inventions was the first microscope. He used it to explore previously unimaginable worlds in drops of pond water, leaves, even his own body fluids. In plaque taken from the mouths of old men he found "an unbelievably great company of living animalcules. . . . All the water . . . seemed to be alive."

Leeuwenhoek had discovered bacteria. It was 1683.

More than three centuries later, the opportunities for a lone, untrained amateur to make a major discovery appear to be long gone. Now that the basic discoveries have been made, it takes millions, or even billions, of dollars to pursue unanswered questions such as mapping the human genome. Science has grown so big that even the most revered Nobel Prize winner is only a small part of an enormous research establishment

Still, the do-it-yourselfers persist. Some have dreams of miracle cures and billion-dollar patents. Others pursue wild conspiracy theories. A few, including Harris, have even dabbled in chemical or biological weapons.

He once tried to use somebody else's credentials to mail-order the organism that causes bubonic plague. He said he needed the bacteria to do research for his book, a guide to biological warfare defense.

Harris might have succeeded if he hadn't called the biological supplier a few days later to inquire about his shipment. The employee who took his call at the American Tissue and Culture Collection in Rockville, Md., became suspicious and notified authorities. The day after the bacteria arrived at Harris' Ohio home, so did a swarm of federal agents. He eventually pleaded guilty to wire fraud and was sentenced to 18 months' probation.

The incident also got Harris kicked out of the American Society for Microbiology (which doesn't require academic credentials for membership). He is the only person ever expelled by the organization.